De 101 02 015 A1 discloses a drivetrain of the generic type. The drivetrain described in said document for a motor vehicle has an engine with a drivable engine shaft or crankshaft, with the engine shaft having a first axial direction. The known drivetrain also comprises a transmission which has a transmission input shaft which is in rotationally driving connection with the engine shaft. Here, the transmission is arranged behind the engine in the first axial direction. Furthermore, the known drivetrain comprises an electric machine with a rotor and a stator, with it being possible for the electric machine to be operated in a generator mode, in which electrical energy can be generated utilizing a relative movement between the rotor and the stator, and a starter mode, in which electrical energy can be converted into a relative movement between the rotor and the stator. Here, the electric machine is coupled by means of a planetary gear set to the engine shaft. The planetary gear set substantially comprises a sun gear, a planet gear carrier with planet gears, and ring gear. The planet gear carrier, which forms the drive input side of the planetary gear set in the generator mode and forms the drive output side of the planetary gear set in the starter mode, is in rotationally driving connection with the engine shaft, while the ring gear, which forms the drive output side of the planetary gear set in the generator mode and forms the drive input side of the planetary gear set in the starter mode, is in rotationally driving connection with the rotor of the electric machine. The sun gear of the planetary gear set can be connected by means of a first actuating device in the form of a freewheel to the stationary housing of the engine in the starter mode of the electric machine. Also provided is a second actuating device in the form of a further freewheel which, in the generator mode, acts between the planet gear carrier and the ring gear in such a way that the planet gear carrier and the ring gear are fixed with respect to one another and the planetary gear set therefore performs a block rotation. In the known drivetrain, the planetary gear set is likewise arranged, together with the electric machine, behind the engine in the first axial direction. More precisely, the planetary gear set is arranged, in the first axial direction, behind the engine and in front of the transmission which likewise follows in the first axial direction.